EN 27842:1991

Automatic steam traps - Determination of discharge capacity - Test methods (ISO 7842:1988)

Migrated from Progress Sheet (TC Comment) (2000-07-10): The results of the PQ procedure has been sent to the BT members proposing to ++ submit the ISO standard to the formal vote.

Kondensatableiter - Bestimmung des Durchflusses - Prüfverfahren (ISO 7842:1988)

Purgeurs automatiques de vapeur d'eau - Détermination du débit - Méthodes d'essai (ISO 7842:1988)

La présente Norme internationale spécifie deux méthodes d'essai permettant de déterminer le débit des purgeurs automatiques de vapeur d'eau conformes à l'ISO 6552.

Avtomatični izločevalniki kondenzata - Ugotavljanje pretočnosti - Preskusne metode (ISO 7842:1988)

General Information

• Status: Withdrawn
• Publication Date: 29-Sep-1991
• Withdrawal Date: 04-Jul-2023
• ICS: 23.040.99 - Other pipeline components
• Technical Committee: CEN/TC 69 - Industrial valves
• Drafting Committee: CEN/TC 69 - Industrial valves
• Directive: 97/23/EC - Directive 97/23/EC of the European Parliament and of the Council of 29 May 1997 on the approximation of the laws of the Member States concerning pressure equipment
• Ref Project: SIST EN 27842:2000 - Automatic steam traps - Determination of discharge capacity - Test methods (ISO 7842:1988)

Relations

• Replaced By: EN ISO 5117:2023 - Automatic steam traps - Production and performance characteristic tests (ISO 5117:2023)
• Effective Date: 19-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2000
$YWRPDWLþQLL]ORþHYDOQLNLNRQGHQ]DWD8JRWDYOMDQMHSUHWRþQRVWL3UHVNXVQH
PHWRGH,62
Automatic steam traps - Determination of discharge capacity - Test methods (ISO
7842:1988)
Kondensatableiter - Bestimmung des Durchflusses - Prüfverfahren (ISO 7842:1988)
Purgeurs automatiques de vapeur d'eau - Détermination du débit - Méthodes d'essai
(ISO 7842:1988)
Ta slovenski standard je istoveten z: EN 27842:1991
ICS:
23.060.01 Ventili na splošno Valves in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

ISO
INTERNATIONAL STANDARD
First edition
1988-12-01
INTERNATIONAL OiGANIZATION FOR STANDARDKATION
ORGANISATION INTERNATIONALE DE NORMALISATION
MEXAYHAPOjJHAFl OPf-AHM3AuMR l-l0 CTAHJJAPTM3A~MM
Automatic steam traps - Determination of discharge
capacity - Test methods
Purgeurs automatiques de vapeur d’eau - Ddtermination du ddbit - M&hodes d’essai
Reference number
ISO 7842: 1988 (E)
ISO 7842 : 1988 (EI
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of
national Standards bodies (ISO member bodies). The work of preparing International
Standards is normally carried out through ISO technical committees. Esch member
body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, govern-
mental and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission (IEC) on all
matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the ISO Council. They are approved in accordance with ISO procedures requiring at
least 75 % approval by the member bodies voting.
International Standard ISO 7842 was prepared by Technical Committee ISO/TC 153,
Valves.
Users should note that all International Standards undergo revision from time to time
and that any reference made herein to any other International Standard implies its
latest edition, unless otherwise stated.
@ International Organkation for Standardkation, 1988
Printed in Switzerland
ISO 7842 : 1988 (E)
INTERNATIONAL STANDARD
Determination of discharge
Automatic steam traps -
capacity - Test methods
1 Scope and field of application ISO 6552, Automatic steam traps - Definition of technical
terms.
This International Standard specifies two test methods to
determine the discharge capacity of automatic steam traps to
3 Test arrangements
ISO 6552.
The test arrangements for condensate capacity determination
are shown in figures 1 and 2.
2 References
All piping and equipment shall be insulated to a value of
ISO 651, Solid-Stern calorimeter thermometers.
m2m°Ch
I S 0 652, Enclosed-scale calorime ter thermome ters.
R > 0,75 x 10-3-
J
ISO 653, Long solid-stern thermometers for precision use.
to reduce thermal losses to a minimuni.
ISO 654, Short solid-stern thermometers for precision use.
The instruments used for the measurements shall comply with
ISO 4185, Measurement of liquid flow in closed conduits - International Standards, if such Standards exist, e.g.
Weighing method.
- ISO 651, ISO 652, ISO 653 and ISO 654 for temperature
measurements;
I S 0 5167, Measuremen t of fluid flow b y means of orifke pla tes,
nozzles and Ven turi tubes inserted in circular Cross-section con-
- ISO 4185, ISO 5167 and ISO 5168 for flow measure-
duits running full. ments.
ISO 5168, Measurement of fluid flow - Estimation of uncer- The condensate removal device shall not be modified in any
tainty of a flow-rate measurement.
way from its commercial form.
Arrangement A
Water
SUPPlY I
(
Steam vent
lLh+zq7 / ?’
u r
I
I
I
.
I
Steam water
c$-f~~
I
c Flash tank
accumulator
Valve 1
r indica:; :*,.,’
Calorimeter
--
--
-- bore ball valve
--
--e
Flow meter
P
qm2
Q
,
I -6 r-7 r r--
tT x r 0
Test device
-Ldo-lH-
Steam supply
11 -*lz*
t
4 (Note21
e (Note 3)
/ / - - .-
~~ Water-coo lled
/- /
Valve 3 /-
CO ndenser
f
Drain
/’
-
m c
--
-
NOTES
--
m2
C
1 The diameter of the pipework from the accumulator to the condensate removal device shall be the same as, or greater than, the diameter of the
pipework to the inlet connection on the device.
Scale
&
2 The distance L 1 shall not exceed IO internal pipe diameters.
3 The distance L2 shall be not less than 10 or more than 20 internal pipe diameters.
Arrangement B
4 The distance 2 shall be measured vertically from the centre of the inlet connection of the condensate removal device.
Figure 1 - Test arrangement for test method A

[so 7842 : lS8 EI
c) the maximum temperature differential (Ae) shall not
4.1 Procedure
exceed 3 OC during the test;
NOTE - Test method A is applicable only to continuous discharge
individual trap inle
d) no t pressure (~3) Observation shall
measurement.
more than 1 % of the average of all observations;
VW bY
Start with all valves closed.
e) the calculated vent steam flow-rate (qm6) shall not ex-
ceed a maximum value equal to an exit velocity of 0,31 m/s
4.1.1 Warm up the System by gradually opening valves 1, 2, in the tank.
3, 4 and 5.
4.1.6 Repeat the operations specified in 4.1 .l to 4.1.5 as
4.1.2 Adjust valves 1, 2 and 3 with valve 4 wide open and
necessary to produce three sets of observations which result in
valve 5 closed to bring the System into equilibrium. Equilibrium three calculated capacity ratings, none of which varies from the
is defined as a steady water level in the accumulator with the average by more than 10 %.
vent valve 3 partially open and a differente of 3 OC or less
showing on the temperature differential indicator.
4.2 Flow calculations
4.1.3 Observe and record the following data as appropriate
qmf = (qml +4m3 -qm4) + 4m8
depending on the method of condensate determination :
steam supply pressure, in barsl);
- Pl=
lrn
c2 -rncl)
= accumulator steam pressure, in bars;
- P2
x 3600
qrnf= At
= trap inlet pressure, in bars;
- P3
= trap outlet pressure, in bars;
- P4
qmf is the discharge flow, in kilograms per hour;
= steam supply temperature, in degrees Celsius;
- 01
is the water flow, in kilograms per hour;
qml
- e2= water supply temperature, in degrees Celsius;
qm3 is the steam flow to heat water
SUPPlY (4ml)l ifl
- A8= temperature differential (subcooling) between
kilograms per hour;
steam in the accumulator and fluid entering the trap, in
degrees Celsius;
(h
3 --hl)
qm3 = 4ml X
- x=
steam supply quality, in per cent;
(h
2 -h3)
- z=
accumulator water level, in metres;
qm4 is the flash steam flow in the
accumulator, in
kilograms per hour;
- At = time interval, in hours, minutes or seconds;
= water supply flow-rate, in kilograms per hour;
- 4ml
(h
3 -h5)
qm4 = (4ml +9m3) x
steam supply flow-rate, in kilograms per hour; (h
- 4m2 = 4 -hg)
-
= mass of condensate and tank at Start, in
mc1
It 02
kilograms; - x 0,31 x 3 600
qm4 , max = -x
Vl
-
= mass of condensate and tank at end, in
mc2
kilograms. is the accumulator storage rate, in kilograms per hour;
qm8
lt is emphasized that figure 1 Shows two alternative test ar- (2 , -22) 3600
?x 02 x X-
qm8= 4
rangements for condensate measurement and that the choice is
At
V2
left to the test laboratory.
mcl and m,2 are as given in 4.1.3;
4.1.4 Record the data specified in 4.1.3 at 5 min intervals for a
water, in kilojoules
is the specific enthalpy of the supply
hl
minimum total of five sets of observations.
kilogram ;
Per
steam, in kilo-
h2 is the specif ic enthalpy of the
SUPPlY
4.1.5 During the test period observations as appropriate shall
joules kilogram
Per
not exceed the following limits :
h3 is the specific enthalpy of saturated at the
=JPPlY
a) the differente between the maximum and minimum
pressu re, in kilojoules per kilogram;
tank level shall not exceed 50 mm;
specific enthalpy of saturated steam in the ac-
b) the maximum value of the tank level shall not exceed h4 is the
450 mm at any time during the test; cumulator, in kilojoules per kilogram;
1) 1 bar = 105 Pa
ISO 7842 : 1988 (El
h5 is the specific enthalpy of satura in the ac- is the time interval, in seconds;
cumulator, in kilojoules per kilogram;
D is the inside diameter of the accumulator, in metres;
vl is the specific volume of saturated steam in the
accumulator, in cubic metres per kilogram;
Zl
is the initial accumulator tank level, in metres;
v2 is the specific volume of saturated in the
accumulator, in cubic metres kilogram;
is the final accumulator tank level, in metres.
Per
ISO 7842 : 1988 EI
4.3 Data sheet
Test Method A
General information
Test No. : . 2 Date of test : . 3 Calculation by : .
Manufacturer’sname : .
SerialNo. : . 6 Size: .
Descriptionandtypeofdevice: .
............................................................................ m
Inside diameter of accumulator, D :
Averaged and corrected test data
................................................................................. bar
9 Steamsupplypressure,p,=
Accumulatorsteampressure,p2= . bar
Trapinletpressure,p3= . bar
12 Trapoutletpressure,p4= . bar
................................................................................. OC
13 Steam supply temperature, 8,
Water supply temperature, e2 . OC
Subcooledtemperature,A0 = . OC
%
16 Steamsupplyquality,X= .
Changeinaccumulatorlevel,Zl -Z2= . m
18 Water supply flow-rate, qml = . kglh
.............................................................................. kg/h
19 Steam supply flow-rate, qm2 =
........................................................................................... s
20 Elapsedtime,At=
Thermodynamic properties
.............................................................................
21 Reference used for steam/water data :
..................................................................... kJ/kg
22 Specific enthalpy of water supply, hl =
..................................................................... kJ/kg
23 Specific enthalpy of steam supply, h2 =
Specific enthalpy of saturated liquid at steam supply pressure, h3 = . kJ/kg
............................................. kJ/kg
25 Specific enthalpy of saturated vapour at accumulator pressure, h4 =
.............................................. kJ/kg
26 Specific enthalpy of saturated liquid at accumulator pressure, h5 =
Specific volume of saturated vapour at accumulator pressure, vl = . m3/kg
Specific volume of saturated liquid at accumulator pressure, v2 = . m3/kg
Calculations
.......................................................................... kg/h
Steam to heat water supply, qm3 =
Item 24 - Item 22
ltem 18 x
ltem 23 - Item 24
Flash steam flow in accumulator, qm4 = . kg/h
(Item 18 + Item 29) (Item 24 - Item 26)
ltem 25 - Item 26
.......................................................................
Water flow-rate to accumulator, qm5 = kg/ h
Item 18 + Item 29 - Item 30
Steamflowtovent,q,6= . kg/h
Item 19 - ltem 29 + Item 30
ISO 7842 : 1988 (El
33 Maximum uncorrected steam flow to vent, qm7 = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
kglh
2 827 x (Item 812
Item 27
34 Vent fraction of maximum, R =
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ltem 32
RZ-------
(shall be < 1 for test to be valid)
Item 33
35 Accumulator storage rate, qm8 = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
kglh
2 827 x (Item 8)2 x ltem 17
Item 20 x Item 28
36 Dischargeflow,qmf= . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
kglh
(Item 18 + Item 29 - Item 30) + Item 35
37 The trap capacity determined by this test is Item 36 for
-
an inlet pressure of Item 11
-
a discharge pressure of Item 12, and
-
a subcooling at the trap inlet of Item 15.

Vent
Safety
valve
Valve
ure reducing valve 1
Press
Cold water
Steam
su PPlY
ass
w Accumulator
Circulator -
1 est -
Vacuum breaker
l ‘uw=3c1-
device
Valve .
.
c
d
J
Gate or full
Temperature controller
bore b
...